Aerobic biodegradation of phenanthrene by a newly isolated Klebsiella sp. DS-1 from wastewater

Abstract

Representative polycyclic aromatic hydrocarbons (PAHs) compounds such as phenanthrene (PHE) derived from multiple anthropogenic activities are contributing to a growing number of concerns about its threats to the global water environment and human health. Microbial degradation is considered to be an increasingly promising approach for PHE removal, while effective PHE biodegraders from in situ environments are yet to be identified and their underlying degradation mechanisms still remain to be understood. Herein, a Klebsiella sp. strain DS-1 was isolated from petrochemical wastewater using PHE as the sole carbon source. The degradation efficiency of PHE was up to 88.4 % at 30 °C and pH 7 within a maximum of 9 days. DS-1 grew actively in wide ranges of environmental factors, such as pH values (5–9), temperature (20 °C–37 °C), and initial concentrations of PHE (20–200 mg/L), with the maintenance of PHE degradability. Genome analysis revealed 14 genes that were involved in PHE biodegradation by DS-1. Detection of metabolic intermediates revealed that strain DS-1 degraded PHE via the phthalic acid pathway. These findings have expanded the knowledge of Klebsiella sp. as an active PHE degrader in wastewater and indicate its potential in the bioremediation of PHE-contaminated aquatic environments.